In general, swimming pools include a pump for drawing water from a drain at the bottom of a pool through a skimmer housing and towards a filter from which the water is returned to the pool. The skimmer housing is often installed at least partially in the ground or beneath a deck surface, having a removable lid and a basket contained therein that retains leaves or other debris from the pool and prevents clogging of the pump and/or filter.
In order to provide sufficient circulation of pool water such that the filter and other components of the pool operate as desired, the pool pump providing the circulation often has a fairly large flow rate. As water is drawn through the drain by the pump, a suction force is created at the surface of the drain, and as such, the drain at the bottom of a swimming pool can pose a significant safety hazard to those occupying of the pool, in particular to a young child or a person of limited physical strength. In the event someone in the pool inadvertently covers the drain with a part of his/her body, the suction force will tend to retain the user against the drain unless the user has sufficient strength to push away from the drain. In fact, in most cases, the suction force is so substantial, i.e., in the range of 500 pounds of force or more, that even an adult of above-average strength will be unable to overcome the suction force being experienced. As a result, there is a strong likelihood that a person will panic, increasing the chance that drowning may result. Even under circumstances where an individual is capable of pushing away from the drain, the possibility of incurring serious injury remains nonetheless.
To overcome the potential for injury or drowning due to the suction force and thus the chance of being drawn against and retained by a swimming pool drain, numerous devices have been developed over the years to reduce and/or eliminate the suction force created during a blockage or entrapment. Some of these devices introduce air to the inlet side of the pump in response to the sensed high suction condition, which results in loss of pump prime. Other devices may interrupt the power source to the pump, thereby causing the pump to cease operation. There are also devices which provide for a conduit to open to the atmosphere upon sensing a predetermined level of suction, which allows air to enter the system and thereby break the vacuum or suction force at the drain.
While certain devices have been proposed, there are numerous problems present with existing devices. For example, many of the devices are very expensive and have multiple moving parts, which increases the likelihood that the device may malfunction or fail to operate as intended. In addition, some of the devices provide false signals triggered by filled drain sumps and/or skimmer baskets, or due to pressure variations created when the pump is first turned on. Moreover, installation of some devices may require excavation or other drastic measures for installation, which greatly increases cost and provides a deterrent to use and integration. Finally, upon installing a particular device, the pump might be damaged or otherwise negatively impacted upon actuation of the device, resulting in the attendant problems of expense and loss of use of the swimming pool.
In view of the above-described problems and limitations, it would be desirable to provide a safety system for reducing and/or eliminating suction forces experienced during entrapment against a pool drain that is simple in operation, cost effective, and easily integrated with existing pools.